all my transaction history has been wiped & my funds are showing zero balance there instead of over 400 BTC , I have contacted support & really hope that this is some glitch, anyone else getting this or similar?

It's all back to normal now phew! Opened it in another Window & it was fine, sorry for the panic - the tab it was open in before went weird or something when I re-booted the comp I suppose, would just happen to be when the only time I was moving a lot of funds through it

Blockchain.info is one of the best online wallets for one primary reason: they encourage you to backup your wallet and provide multiple ways of letting you do that.

Your entire blockchain wallet can be copied encrypted or unencrypted out of the website; it provides a method of converting your wallet to a paper wallet; you can even import keys from your desktop wallet or other online wallets and use blockchain.info as an alternative access mechanism.

I realise that you didn't lose anything in this case, but if you had, I'm afraid you would only have had yourself to blame. The tools are there, and are easy to use, people -- use them.

piuk has also contributed a patch for MultiBit so that you can import blockchain.info wallet backups into MultiBit.This includes the encrypted and double encrypted ones. It is included in the current release on http://multibit.org

Due to how the data is stored, it needs a full replay of the blocks to get the balance (say 2 hours on wifi) so it is more a "get out of jail free" card than something you would use day to day.

thanks for the tips, it's really not working though today & I've tried everything - I've wasted hours as I assumed it must be my computer misbehaving - I see there's another thread on this in tech support so I'll follow that